ABSTRACT Pilot and Feasibility Project Core Discovery is iterative, and each new finding provides insights that are impactful, leading to additional questions that require further clarification and study. The Pilot and Feasibility Project Core has provided the Genetic Dis- orders of Mucociliary Clearance Consortium (GDMCC) with the flexibility to pursue these questions. Throughout its existence, the GDMCC has supported innovative and impactful pilot and feasibility projects to advance our understanding of rare lung diseases, many leading to independent grant support. Projects have striven to bring investigators from multiple disciplines together to advance diagnostic techniques and therapeutic targets that impact management of chronic suppurative respiratory diseases. These projects align with the goals of the overall activities of the Rare Diseases Clinical Research Network. While historically centered on primary ciliary dyskinesia, the scope of these projects will expand to include inherited, rare primary immunodeficiencies that lead to chronic suppurative respiratory disease, a new focus for the Consortium. Our overall goal is to sup- port pilot and feasibility projects from early-career investigators from across the Rare Diseases Clinical Research Network, which will advance our understanding of chronic suppurative respiratory diseases, provide insights into the pathogenesis of these diseases, yield novel approaches that better define phenotype, and test and validate endpoints that are critical for clinical trial readiness. The GMDCC Pilot and Feasibility Project Core has been highly successful. We plan to support proposals focused on the overall goals of the Consortium; these include advancing our insights of the genetic bases and patho- physiology of chronic suppurative respiratory diseases, improving diagnostic capabilities, providing a better un- derstanding of the clinical course, and potentially identifying novel therapeutic targets for individuals with primary ciliary dyskinesia and primary immunodeficiencies. We will apply clear established criteria for the peer-review process in choosing projects that meet scientific merit, and will regularly monitor and evaluate progress of these projects. Finally, expected research milestones, infrastructure, mentorship, and funding sources (including insti- tutional and other extramural sources) will be defined and adapted to the individual pilot and feasibility projects, thus enhancing their likelihood of success.